The mean 222Rn concentration of 1.4070.03 Bql1 in the 20 groundwater samples of this study is also lower than the WHO
advised level of 100 Bql1. Fifty percent of groundwater samples analysed have 226Ra levels in excess of
the USEPA recommended maximum contaminant level of 0.185 Bql1. The occurrence of elevated
concentrations of 226Ra in groundwater samples was explained by pH and alkaline conditions.